We present preliminary results for the kaon semileptonic form factors
using the PACS10 configurations, whose physical volume is more than
(10 fm)$^3$ at the physical point with the lattice spacings of
0.085 and 0.064 fm.
The configurations were generated using the Iwasaki gauge action and $N_f=2+1$
stout-smeared Clover quark action.
For the continuum extrapolation, we calculate the form factors
with the local and conserved vector currents.
The form factors in the two lattice spacings are extrapolated
to the continuum limit using a fit function
based on the NLO SU(3) ChPT formula with terms corresponding to finite lattice
spacing effects.
The value of $|V_{us}|$ is determined
using our preliminary result of the form factor at the zero momentum
transfer in the continuum limit.
The result is compared with recent lattice results,
and also predictions of the standard
model from the unitarity of the Cabibbo-Kobayashi-Maskawa (CKM) matrix.